/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.skatiger.jrove.util;

/**
 * Converts characters outside of latin-1 set in a string to numeric character
 * references.
 * 
 */
public abstract class UnicodeEncoder {
    /**
     * Encodes the given string, so that it can be used within a html page.
     * 
     * @param string
     *            the string to convert
     */
    public static String encode(String string) {
        if (string == null) {
            return "";
        }

        StringBuilder sb = null;
        char c;
        for (int i = 0; i < string.length(); ++i) {
            c = string.charAt(i);
            if (((int) c) >= 0x80) {
                if (sb == null) {
                    sb = new StringBuilder(string.length() + 4);
                    sb.append(string.substring(0, i));
                }
                //encode all non basic latin characters
                sb.append("&#");
                sb.append((int) c);
                sb.append(";");
            } else if (sb != null) {
                sb.append(c);
            }
        }

        return sb != null ? sb.toString() : string;
    }

}
